var lis = document.getElementsByTagName("h5"),
    ems = document.getElementsByTagName("em"),
    divs = document.getElementsByClassName("bottom");
for (let j = 0; j < lis.length; j++) {
    lis[j].onmouseover = function () {
        for (var i = 0; i < divs.length; i++) {
            lis[i].className = "";
            ems[i].className = "";
            divs[i].className = "bottom";
        }
        this.className = "active ";
        ems[j].className = "active";
        divs[j].className = "active bottom";
    }
}

